Author + information
- Received June 2, 1992
- Revision received September 30, 1992
- Accepted October 28, 1992
- Published online May 1, 1993.
- Piotr Kulakowski, MD∗,
- Yaver Bashir, MRCP,
- Spencer Heald, MRCP,
- Vince Paul, MRCP,
- Mark H. Anderson, MRCP,
- Sheila Gibson, RN,
- Marek Malik, MD, PhD, FESC, FACC and
- A.John Camm, MD, FRCP, FESC, FACC
- ↵∗Address for correspondence: Piotr Kulakowski, MD, Department of Cardiological Sciences, St. George's Hospital Medical School, Cranmer Terrace, London SW17 ORE, England, United Kingdom
Objectives. The aim of this study was to assess the ability of the signal-averaged electrocardiogram (ECG) to predict the efficacy of procainamide.
Background. The main role of the signal-averaged ECG has been the identification of postinfarction patients at risk of sudden death. Prediction of the efficacy of antiarrhythmic drugs represents another potential clinical application of this technique.
Methods. The study examined the effects of procainamide on the time domain and spectral temporal analysis of the signalaveraged ECG in relation to the results of programmed ventricular stimulation studies in 31 patients with inducible sustained monomorphic ventricular tachycardia.
Results. Procainamide significantly prolonged the total and the initial QRS complex and low amplitude signal durations (mean ± SD135 ± 30 vs. 161 ± 46 ms, p < 0.0001; 87 ± 16 vs. 98 ± 20 ms, p < 0.0001, and 48 ± 23 vs. 63 ± 36 ms, p < 0.001, respectively) whereas the root-mean-square voltage of the total QRS complex and of the last 40 ms of the QRS complex was significantly reduced (mean ± SD 112 ± 36 vs. 87 ± 36 μV, p < 0.0001; 21 ± 19 vs. 13 ± 12 μV, p < 0.002, respectively). The results of spectral temporal mapping of the signal-averaged ECG were similar before and after procainamide administration. Procainamide prevented the inducibility of sustained ventricular tachycardia or prolonged the cycle length of ventricular tachycardia by ≥100 ms in 16 patients (52%) (responders). The fractional prolongation of the total QRS duration was significantly greater in responders (26 ± 15%) than in nonresponders (10 ± 10%) (p < 0.002) and, when this prolongation was ≥15%, identified responders with a sensitivity of 94%, a specificity of 87% and an overall predictive accuracy of 90%.
Conclusions. The effects of procainamide on inducibility of ventricular tachycardia during programmed ventricular stimulation can be predicted by the degree of drug-induced prolongation of the signal-averaged QRS complex.
☆ This study was presented in part at the 13th Annual Scientific Session of the North American Society of Facing and Electrophysiology, Chicago, Illinois, May 1992. It was supported by a research fellowship to Dr. Kulakowski from the European Society of Cardiology, Rotterdam, The Netherlands and in part by a grant from the British Heart Foundation, London.
- Received June 2, 1992.
- Revision received September 30, 1992.
- Accepted October 28, 1992.